NMR Spectroscopy: Principles and Applications

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nmr spectroscopy : Principles and ApplicationsNagarajan MuraliCoherence Selection & How A Spectrometer WorksLecture 8Coherence SelectionWe have seen several homonuclearand heteronuclear1D and 2D experiments. It is instructive to understand how these various experiments select the information by retaining the desired coherence transfers and suppressing the undesired transfers. For example in DQFC we said we will retain only the DQ coherences between the second and third Selection in DQFCAfter the second 90opulse we retain only the DQC. )22(21)sin()cos(2 22()22(21)sin()cos(2)sin()cos(2121112112 1212121112112111211xzzxxxyyxxyyxyxIIIItJ tIIIIIIIIItJtIItJt DQZQThird 90opulseCoherence SelectionThe spins in the sample evolve according to the interactions active during the pulse sequence and transform depending on the axis along which the RF pulses are applied. There are two ways of achieving the coherence selection (1) by phase cycling the RF pulses and the receiver and (2) by applying pulsed field gradients.)

NMR Spectroscopy: Principles and Applications Nagarajan Murali Coherence Selection & How A Spectrometer Works Lecture 8. Coherence Selection We have seen several homonuclear and heteronuclear 1D and 2D experiments. It is instructive to understand how these various

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